Sounds like you need to un-install the current version of zone alarm that you have and re-install from a previous version.
If you dont have the original binary you can find a historical list of them to download from here:
Old Version of ZoneAlarm Download
Using add/remove programs in control panel will allow you to uninstall zone alarm - there may also be an uninstall icon withing the application folder on the start menu.
Cheers